scaffld
Practice with an AI tutor

Master system design interviews

scaffld is an interactive playground where you architect real systems on a canvas and get instant, expert feedback from an AI tutor.

Free to start · Sign in to save and resume your attempts.

Design canvas
Client
API
Cache
Database
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Real interview problems

Work through a curated catalog of system design challenges, from URL shorteners to global-scale feeds.

AI tutor feedback

Get guided, real-time feedback on your architecture as you design — like pairing with a senior engineer.

Track your progress

Pick up right where you left off. Every attempt is saved so you can resume and measure improvement.